I made a discovery today about core files on Mac OS. It seems whenever an application crashes in a certain way, it's memory image is written into a hidden folder on Mac OS: /cores
Since EigenD crashes occasionally, and when it does it usually has grabbed all the memory on your system for soundfonts and AUs, these files can be BIG. There's 60 odd gigs worth on my system!
I found some instructions on how to remove them and prevent future core files being created here:
http://blog.e-shell.org/14